There are countless beauty pageants nowadays, both for adults and children.
Negative points about beauty contests:

Participants have to be scantily clad.
Participants' dignity is reduced.
There is bad influence for children.

It is shallow to compete on physical appearance.
The objectification reinforces the idea that women are valued primarily on physical appearance.
So many women will spend a lot on appearance, even with cosmetic surgery.
Many will have exceptional fear of getting old.

Participants need to wear some clothes that are expensively yet poorly designed.

The rating is given subjectively and there is no clear standard. Beauty is in the eye of the beholders.

There may be an unspoken rule to accept indecent proposal in order to get into the competition.